Textiles, and particularly cotton and cotton blend textiles, are often treated with silicone finishing agents to provide softness, improve tear strength, flex abrasion, processibility and wrinkle recovery. These finishing agents are generally applied to the textile from aqueous systems in pad-dry-cure operations.
Commonly employed types of silicone finishing agents are the polysiloxanes containing pendant organic groups. The silicone finishing agents which have been typically used heretofore have hydrophobic properties and result in the fabrics having little or no water absorbency. When hydrophilic silicone copolymers are used, the textiles have improved hydrophilic properties, but these finishes generally have poor durability. To improve the durability of the hydrophilic silicone finishes, reactive or curable organomodified silicones are generally used.
One example of the efforts to produce durable silicone finishes on textiles is disclosed in U.S. Pat. No. 4,459,383. The fiber-treating composition includes at least two reactive organosilicones which are able to react with each other and form durable finishes. The organomodified silicones include (1) an epoxy-substitutes siloxane and (2) an amino or carboxy-substituted and polyether-containing siloxane copolymer. The epoxy silicone is reacted with the amino-containing siloxane or alternatively the carboxyl-containing siloxane during curing to crosslink the siloxanes onto the fibers.
Other silicone finishing agents include silicone copolymers having polyoxyalkylene substituents and hydrolyzable di- or trialkoxysilyl groups. The silicones are applied to the fabric in the presence of moisture where the alkoxysilyl groups are hydrolyzed and cured at elevated temperatures. One example of this form of silicone finishing agent is disclosed in U.S. Pat. No. 4,283,519. A hydrophilic organosilicone includes a trialkoxysilyl pendant group and a polyoxyethylene/polyoxypropylene chain terminated with a hydrogen or an acyl group. The silicone is applied to the fabric and cured by heating in the presence of a catalyst.
U.S. Pat. No. 4,758,646 discloses a bis (alkoxysilyl) polyether copolymer as a fabric sizing agent. The sizing agent is applied to the fabric and cured by heating to produce a hydrophilic finish having antistatic and soil release properties.
Glyoxal has been known to react with cotton and produce durable press finishes for cotton related fabrics such as that disclosed in U.S. Pat. No. 4,472,167. In this patent, an aqueous solution of glyoxal, glycol and an acid catalyst is applied to a cellulosic textile and cured by heating. The glyoxal is reported to form acetal crosslinks with cellulose. The glycol is added as a coreactant additive to modify the length of the crosslinks in the network. An optional silanol-terminated silicone is reported to produce a treated fabric having considerable water repellency.
U.S. Pat. No. 4,269,603 discloses a durable press treatment for textile fabrics using an aqueous solution of glyoxal, a reactive hydrophobic silicone and a catalyst. The treating composition is cured at about 177.degree. C. to 204.degree. C. This curing temperature has the disadvantage of producing a significant loss of tear strength of the fabric. The treating composition is reported to impart wrinkle resistance and smooth drying performance.
The present invention is directed to a method of producing hydrophilic silicone finishes for cellulose-containing textiles, using glyoxal to bind silicone copolymers to the textile. The resulting silicone finishes are durable to washing and impart soft hydrophilic properties and durable press properties to the treated fabric.